Apparatus for gravel packing wells



Oct. 13, 1942. H. M VMCCLAlN APPARATUS FOR GRAVEL PACKING WELLS FiledSept. 19, 1940 INVEN-roR fla/mer f7. L CMM' -rToRNEY r J L #on i. .J fn.F f

L /NER HANGER Patented Oct', 1942 2,299,057 APPARATUS ron Gnavzr. Pacxmawms f Hubert M. melun, oklahomcity. omhusignor to Socony-Vacnum OilCompany, Incorporated, New York, N. Y., a corporation of New YorkApplication September 19, 1940, No. 357,370 3 Claims. (Cl. 16d-J) Thisinvention is directed to apparatus for gravel packing a well to be usedfor the production of petroleum or gas therefrom or for use.

as a channel for the introduction of gas or water into a subterraneanformation.

Gravel packing is the operation of filling the space between theformation walls and the liners. l

at the bottom oi' a well, with screened gravel particles of desiredsize. 'I'he packing so placed serves several functions, among the chiefof which are to prevent the formation walls from sloughing olf andstopping use of the hole, to prevent plugging of the liner with sand,and to permit of proper iiow conditions between the formation and theliner.

In general, the present methods of gravel packing, either a water wellor an oil well, vary only in detail and may be classified as: I(1)Reverse circulation method, in which the gravel is in- Jected betweenthe casing and the tubing on which the liner is run and through whichthe circulating iiuid returns to the surface; and (2) Normal circulationmethod, in which the gravel is pumped down the hole inside the tubing,and the circulating fluid returning between the tubing and casing.

When considering the reverse circulation method, the procedure usuallyincludes underreaming the open hole below the casing seat, to provideample annular space outside the liner to permit free passageway for thegravel without bridging at any point up the hole below the casing seat.Also since the space between the casing and liner will always be smallerthan any enlarged hole below the casing seat, the size of casing andliner become important and should provide the largest space possiblewhen the gravel is injected by the reverse circulation method. Whenusing th'e normal circulation method the size of the casing and linerare not so important. The liner is usually run on a string of tubing,with suitable setting tools or connections whereby the tubing can bebacked o from the liner after the gravel has been placed back of theliner.

vAfter the liner is placed in position-on the bottom of the hole for thereverse circulation method and before backing tubing off from liner, thecirculating fluid (either a drilling mud or oil) is pumped into the holebetween the tubing and casing, down back of the liner through theperforations in the liner shoe, and up through the inside of the tubingto establish circulation. A thin cement lining is usually run on theinside of the perforated liner to close the-perforation so the fluidwill. circulate down back of the liner to the perforated shoe on thebottom of the liner.

With free circulation the gravel is introduced into the circulatingfluid stream at the casing head by means oi suitable gravel pumps and/ora pressure gravel lubricator. As the gravel is deposited back of theliner the circulating fluid is pumped to the surface through the tubing.

While gravel packing with the reverse circulation method the greatesthazard is the bridging of the gravel in the restricted space between thetubing and casing above the liner, resulting in sticking the tubing,which usually results in Aan expensive fishing job to recover thetubing. Also, while gravel packing with the reverse circulation methodthere is always the possibility of the hole caving. 'I'his caving wouldbe partially due to agitation while circulating an improper drillingfluid in and out of the hole across the face of the enlarged open holebelow the casing seat. 'I'his would usually result in the bridging ofthe gravel back of the liner before the entire space back of the linerhas been filled with gravel, and thereby necessitate pulling the tubingand liner and cleaning the hole out before attempting another gravelpack. V

The normal circulation method includes underreaming of the hole belowthe casing seat, and the setting of the liner in place in the hole withtubing. Instead of circulating the fluid and gravel into the holethrough the annular space between the casing and tubing, it is pumpedinto the hole through the tubing, down through the liner and check valvein the bottom of the liner and up the hole back of the liner. The checkvalve prevents the gravel from iiowing back and entering the liner afterthe circulating pumps are shut down. As the gravel is placed in theannular space back of the liner the iiuidis circulated up to the surfacethrough the annular space between the tubing and casing.

The normal circulation method reduces the possibility of the gravelbridging due to caving back of the liner, because the fluid, as itcirculates back oi the liner, lifts the cavings and carries them up backof the liner as the gravel comes in from the bottom through the linercheck valve. However, the possibility of the gravel bridging in thetubing and/or liner above the check valve is still prevalent in thismethod of gravel packing.

'I'he principal object of this invention is the provision of a methodand apparatus, useful in gravel packing, whereby the diillculties ofpresent methods may be avoided to a large degree. A further object isthe provision of a method of, gravel packing capable of eliminating theusey of tubing and utilizing the full interior area of the casing forpassage of gravel.

A major object is the provision of a method oi.' gravel packing wherebythe washing action of circulated fluids upon the formation being packedis minimized.

An important object is the provision of a method of gravel packinginvolving a minimum of operative steps.

These objects are obtained by use of the method here disclosed whichwill be most readily understood by reference to the drawing attachedhereto.

Fig. 1 is a sectional elevational view ofthe apparatus in the well holeduring gravel packing.

Fig. 2 is an enlarged view of the portion of tube 9 of Fig. 1 thatcontains plug IB and ports I showing details of construction.

Fig. 3 is a cross section of Fig. 2 taken along line A-A looking in thedirection indicated.

Fig. 4 is a similar view after the gravel packing is completed, plug I6displaced, and the well is producing through tubing 20.

In Figure 1, 5 denotes the bore hole, in which there has been seated acasing 6, which is cemented at 1. The well, after casing, has beenunderreamed to increase its diameter below the casing seat at shown at8. A suitable liner 9 has been placed within the underreamed hole 8 andpositioned by means of liner hanger I0, terminating at its upper end ina coupling II, the whole being supported in and packed to the casing bya conventional liner hanging packer I2.

The liner is provided with slots I3, as is usual, for production, theseslots extending throughout a desired portion of the length of the liner.At a point I4, above the production slots, but at a point below thebottom of the casing 6, there is provided in liner 9 a construction bestunderstood by referring to Figures 2 and 3, wherein the liner 9 is shownto be equipped at level I4 with three large slots or windows I5,distributed as shown in Figure 3 which is a section o1' the liner atA-A. Below these windows and within liner 9 is a cone topped plug I6,supported within the liner by pins I1. This plug may be made, as shown,of wood, or it may be of soft metal, or concrete, or Bakelite, or anyfrangible material which may later be broken or removed by drilling, orwhich may be pushed to the bottom of the liner. If desired, the plug maybe encased in a metal sleeve I8. The cone shaped top of plug I6 is soplaced relative to the slots I5 that it forms a directive slope wherebymaterial such as gravel, will be forced to pass entirely out throughsaid slots.

With the` liner and packer set, and the tubing entirely removed, all asshown in Figure 1, a mixture of gravel and a small amount of fluid isdropped into the casing at the surface. In a noniiowing oil well, theiluid may be oil or a petroleum fraction. In a salt water disposal wellthe :duid may be water. In an oil well under pressure, the uid may beoil and the mixture may be introduced at the surface through a properlubricator as is well known. Other appropriate modifications are obviousand well lmown. The gravel falls to the bottom of the casing and passesout through the slots I5, to collect around the liner as shown at I9.This procedure is followed until To complete the well for service, asshown in Figure 4, a string of tubing 20 is run into the well. Thistubing 2II ends in an adaptor 2|, carrying an adaptor packing 22, whichis set down on the coupling II of the liner hanger I0. Depending fromthe adaptor 2l .is a tubing 23 which is of slightly smaller externaldiameter than the internal diameter of liner 9 and which extends intoliner 9 to a suillcient distance to extend beyond and'blank of! theslots I5 in liner 9.

The advantages oi this method of gravel packing are as follows:Elimination of the possibility of sticking a string of tubing by gravelbridging above the liner.

Elimination of the possibility of gravel bridging due to restrictedspace between casing and liner. Restricted space is eliminated becauseline is hung in hole with a packer. The three slots in top end of linerabove wooden plug provide larger cross sectional area to gravel packthrough.

In case gravel does bridge above the wooden plug in top of liner, it canbe removed readily with suitable bailer, eliminating necessity ofpulling tubing as in the case of both the reverse and normal circulationmethods.

Possibility of gravel bridging back of liner due to caving conditions isreduced because the uid used to inject gravel back of liner is pumpedinto the surrounding formation and thereby maintains a constant pressureon the face of the open hole and partially eliminates the washing actionof the circulating fluids.

I claim:

1. An apparatus for completing and gravel packing a well comprising aliner equipped with a liner hanging packer, in the Wall of said liner aplurality of slots of large cross-sectional area for the passage ofgravel, said slots being so located longitudinally as to be just belowthe casing bottom when the lining is set, and within said liner afrangible plug placed just below said slots.

2. An apparatus for completing and gravel packing a well comprising aliner equipped with a liner hanging packer, in the wall of said liner aplurality of slots of large cross-sectional area for the passage ofgravel, said slots being so located longitudinally as to be just belowthe casing bottom when the liner is set, and within said liner a conicaltopped frangible plug so placed as to plug the liner below said slotsand divert gravel through said slots.

3. An apparatus for completing and gravel packing a well comprising a'liner equipped with a liner hanging packer, in the wall of said liner aplurality of slots of large cross-sectional area for the passage ofgravel, said slots being so located longitudinally as to be just belowthe casing bottom when the liner is set, within said liner a frangibleplug placed just below said slots, and a liner tube adapted to beinserted in said liner after gravel packing and to extend thereintosuiiiciently to seal off said slots.

HALBERT M. MCCLAIN.

